Which flow type occurs at an early time in wells hydraulically fractured with a finite-conductivity fracture?

Which flow type occurs at an early time in wells hydraulically fractured with a finite-conductivity fracture?

• A. Bilinear Flow
• B. Radial Flow
• C. Pseudosteady-State Flow
• D. Spherical Flow

Answer: (A)

At very early times, the pressure disturbance in a well with a finite-conductivity fracture is confined to a thin region around the fracture, so the flow field is effectively two-dimensional. The fracture itself resists flow, and fluid enters or leaves the fracture from the surrounding rock, creating flow fields along the fracture length and into the adjacent matrix. This combination yields two linear directions of diffusion in the plane, which is the essence of bilinear flow. In other words, the early-time response is governed by diffusion in two directions (along the fracture and into the nearby matrix) rather than by a single radial spreading away from the well. As time goes on, the flow pattern evolves toward other regimes (like radial or pseudo-steady-state) as the matrix farther from the fracture starts to contribute more significantly to the flow.

At very early times, the pressure disturbance in a well with a finite-conductivity fracture is confined to a thin region around the fracture, so the flow field is effectively two-dimensional. The fracture itself resists flow, and fluid enters or leaves the fracture from the surrounding rock, creating flow fields along the fracture length and into the adjacent matrix. This combination yields two linear directions of diffusion in the plane, which is the essence of bilinear flow. In other words, the early-time response is governed by diffusion in two directions (along the fracture and into the nearby matrix) rather than by a single radial spreading away from the well. As time goes on, the flow pattern evolves toward other regimes (like radial or pseudo-steady-state) as the matrix farther from the fracture starts to contribute more significantly to the flow.